1. Field of the Invention
The present invention relates to an electric drive vehicle that travels in, for example, mines or like while receiving electric power from trolley lines and particularly, to a technology that displays information for supporting the driving of an electric drive vehicle.
2. Description of the Related Art
Where a dump truck is electrically driven to travel in a mine with trolley lines installed, it is requested to drive the dump truck so that a slider plate of a current collector provided on the dump truck movably up and down does not deviate from the trolley lines. There has been known a technology that controls the vertical position of a slider plate so as not to let the slider plate deviate from trolley lines. For example, Japanese Unexamined Patent Application Publication No. 2005-94952 describes a configuration wherein the image of a current collector section is taken by a camera from below, wherein the positional relation between the current collector section and trolley lines is calculated by analyzing the image taken by the camera, and wherein the current collector section is moved up and down based on the calculation result (refer to abstract).
However, the aforementioned Japanese Unexamined Patent Application Publication No. 2005-94952 places the premises on a trolley bus that travels urban districts with paved road surfaces, and thus, the situation that the trolley bus deviates from trolley lines in a right-left direction is hard to occur. Therefore, it is sufficient for the current collector section to be able to adjust the position of a slider plate in the vertical direction. However, in mines, the state of road surfaces is not necessarily satisfactory. In order for a dump truck not to deviate from trolley lines in a right-left direction, a driver of the dump track is required to manipulate a steering wheel while not only visually observing the situation ahead but also checking the relative position in the right-left direction between the trolley lines ahead and above and the dump truck through visual observation, and thus, the burden on the driver is heavy.
Therefore, in order to mitigate the burden on the driver, it is conceived to display on a monitor the image covering the slider plate and the trolley lines acquired by the camera described in, for example, the aforementioned Japanese Unexamined Patent Application Publication No. 2005-94952. However, because the prior art described in the Japanese Unexamined Patent Application Publication No. 2005-94952 is designed to take the images of the slider plate and the trolley lines from below with the camera, displaying the taken image on the monitor as it is gives rise to a problem that the driver has a difficulty in grasping the positional relation between the trolley lines and the vehicle body.
Further, in the Japanese Unexamined Patent Application Publication No. 2005-94952, a closed circuit is configured by two trolley lines, wherein one of the trolley lines is a high-voltage side while the other trolley line is a ground side. In this configuration, an anxiety arises in that the image accuracy of the camera will be deteriorated by suffering the influence of noise from the trolley line on the high-voltage side.